Tractor



FIG. 1 is a left side view of the tractor showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a rear side view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a left perspective view thereof; and,

FIG. 7 is a right perspective view thereof.

The broken line showing of the tractor is included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

The ornamental design for a tractor, as shown and described. 